// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2012 Désiré Nuentsa-Wakam <desire.nuentsa_wakam@inria.fr>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
/*

 * NOTE: This file is the modified version of [s,d,c,z]copy_to_ucol.c file in SuperLU

 * -- SuperLU routine (version 2.0) --
 * Univ. of California Berkeley, Xerox Palo Alto Research Center,
 * and Lawrence Berkeley National Lab.
 * November 15, 1997
 *
 * Copyright (c) 1994 by Xerox Corporation.  All rights reserved.
 *
 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY
 * EXPRESSED OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
 *
 * Permission is hereby granted to use or copy this program for any
 * purpose, provided the above notices are retained on all copies.
 * Permission to modify the code and to distribute modified code is
 * granted, provided the above notices are retained, and a notice that
 * the code was modified is included with the above copyright notice.
 */
#ifndef SPARSELU_COPY_TO_UCOL_H
#define SPARSELU_COPY_TO_UCOL_H

namespace Eigen {
namespace internal {

/**
 * \brief Performs numeric block updates (sup-col) in topological order
 *
 * \param jcol current column to update
 * \param nseg Number of segments in the U part
 * \param segrep segment representative ...
 * \param repfnz First nonzero column in each row  ...
 * \param perm_r Row permutation
 * \param dense Store the full representation of the column
 * \param glu Global LU data.
 * \return 0 - successful return
 *         > 0 - number of bytes allocated when run out of space
 *
 */
template<typename Scalar, typename StorageIndex>
Index
SparseLUImpl<Scalar, StorageIndex>::copy_to_ucol(const Index jcol,
												 const Index nseg,
												 IndexVector& segrep,
												 BlockIndexVector repfnz,
												 IndexVector& perm_r,
												 BlockScalarVector dense,
												 GlobalLU_t& glu)
{
	Index ksub, krep, ksupno;

	Index jsupno = glu.supno(jcol);

	// For each nonzero supernode segment of U[*,j] in topological order
	Index k = nseg - 1, i;
	StorageIndex nextu = glu.xusub(jcol);
	Index kfnz, isub, segsize;
	Index new_next, irow;
	Index fsupc, mem;
	for (ksub = 0; ksub < nseg; ksub++) {
		krep = segrep(k);
		k--;
		ksupno = glu.supno(krep);
		if (jsupno != ksupno) // should go into ucol();
		{
			kfnz = repfnz(krep);
			if (kfnz != emptyIdxLU) { // Nonzero U-segment
				fsupc = glu.xsup(ksupno);
				isub = glu.xlsub(fsupc) + kfnz - fsupc;
				segsize = krep - kfnz + 1;
				new_next = nextu + segsize;
				while (new_next > glu.nzumax) {
					mem = memXpand<ScalarVector>(glu.ucol, glu.nzumax, nextu, UCOL, glu.num_expansions);
					if (mem)
						return mem;
					mem = memXpand<IndexVector>(glu.usub, glu.nzumax, nextu, USUB, glu.num_expansions);
					if (mem)
						return mem;
				}

				for (i = 0; i < segsize; i++) {
					irow = glu.lsub(isub);
					glu.usub(nextu) = perm_r(irow); // Unlike the L part, the U part is stored in its final order
					glu.ucol(nextu) = dense(irow);
					dense(irow) = Scalar(0.0);
					nextu++;
					isub++;
				}

			} // end nonzero U-segment

		} // end if jsupno

	}							 // end for each segment
	glu.xusub(jcol + 1) = nextu; // close U(*,jcol)
	return 0;
}

} // namespace internal
} // end namespace Eigen

#endif // SPARSELU_COPY_TO_UCOL_H
